1. Field of the Invention
The present invention provides an improved system and method for dispensing dehydrated culture media (DCM) powder into containers for preparation of culture media. More particularly, the present invention relates to improved manual and automated systems and methods for dispensing DCM powder into vessels or media preparation instruments in a sanitary manner to avoid contamination by DCM powder dust to the surrounding area.
2. Description of the Related Art
Microbiology laboratories are required to produce large quantities of agar based growth media to use in the growth of bacteria and other microorganisms. Regardless of the specific agar media formulation used, most media are prepared by mixing powdered dehydrated culture media (DCM) with water and then sterilizing the mixture in an autoclave to insure the growth media is free of contamination. The dehydrated media powder, which is ground very fine, is typically delivered to the laboratory in plastic containers of varying sizes. A laboratory technician will typically scoop or pour out and weigh the required amount of DCM powder, add the appropriate amount of water, and mix and warm the mixture using, for example, a magnetic stirring motor with stir bar. Once the DCM and water have been completely mixed, the mixture is sterilized by autoclave or media preparator.
As used in most laboratories, DCM is a very light and fine powder. Some DCM formulations are highly toxic and all are irritants to some degree. When poured, DCM often forms a cloud of dust that rises above and around the technician who is dispensing the powder. This “media cloud” or “dusting” causes several problems. Often the technician will inhale DCM dust, which can be a health hazard. Additionally, as the dust settles it leaves a film of agar on surrounding laboratory surfaces. Because DCM typically is used in areas that tend to be warm and moist due to the close proximity of steam-producing autoclaves, the media dust leaves a sticky film that is difficult to clean and that increases the likelihood of surface contamination. Moreover, because the DCM is a fine powder, it tends to penetrate into very small spaces in the laboratory, including the inside surfaces of scientific instruments where the resulting film can cause damage and excess wear over time.
Another problem is that the process of dispensing DCM is time consuming since a precise quantity should first be weighed prior to adding water. A further problem is that mixing large batches of DCM with water, e.g., batches of certain types of media larger than 10 liters, often requires DCM and water to be added alternately in limited quantities each time to avoid clumping of the media. This increases the time needed to create the media, contributes to inaccuracies and errors and increases the likelihood of DCM dusting. A further problem is that technicians sometimes are imprecise in their measurements of DCM or water. It is also important for technicians to be able to readily identify different containers including different types of media cultures without close inspection, to thus increase the efficiency of the dispensing process.
Accordingly, a need exists for an improved system and method for dispensing DCM in a sanitary manner to avoid contamination to surrounding areas and minimize exposure to technicians and other personnel.